The present invention relates generally to a programmer used in conjunction with an implantable medical device. More specifically, the present invention relates to an improved graphical display of selected information in conjunction with an implantable medical device.
Implantable medical device systems known in the art comprise several components, including an implantable medical device, such as a pacemaker, pacing and/or sensing leads (leads), and a programmer. The leads connect the implantable medical device to the heart of a patient. The programmer provides multiple functions, including (a) assessing lead performance during a pacemaker or defibrillator implantation, (b) programming the implantable medical device, and (c) receiving feedback information from the implantable medical device for use by a clinician or physician (operator). By measuring the electrical performance of a lead, the programmer aids the operator in selecting an electrically appropriate site for the placement of the lead(s).
In conjunction with programming the implantable medical device system, it is critical for an operator to determine whether the leads are properly positioned within a passageway of a heart, such as an atrium or ventricle of the patient.
A disadvantage of prior art programmers involves the techniques used to display information to the operator during an implant procedure. Most prior art systems graphically display several, continuous-time waveforms, which are constantly scrolling across the screen at a rapid rate. The remaining information is presented to the operator in the form of numerical data. In order to determine if a specific lead is properly positioned within a passageway of the heart, the operator must review not only the graphical display of the continuous-time cardiac waveform scrolling across the display, but also review a variety of numerical data. The operator must then have the ability and understanding to process the various data shown both graphically and numerically in order to determine if the lead is positioned to ensure proper operation of a later attached implantable medical device.
U.S. Pat. No. 5,713,937 to Nappholz et al. discloses a pacemaker programmer menu with selectable real or simulated implant data graphics. This reference discloses a graphical display of two separate characteristics of an implantable medical device system, such as a heartbeat of a patient and a ventricular pacing rate as applied to a medical implant.
Other disclosures relating to the same general issues are listed below in Table 1.
The prior art in general, as well as the Nappholz et al. reference in particular, have certain disadvantages. For example, the display units of the prior art patents display a continuous-time cardiac waveform. This waveform is continuously scrolling across the display. Once the continuous-time waveform reaches the end of the display, the waveform disappears and a new continuous-time waveform is generated in real time and scrolls across the screen. Thus, it is virtually impossible for an operator to determine the configuration of the waveform signal, or to determine the amplitude of the signal. Additionally, the operator must evaluate various numerical data in conjunction with the graphical display to determine if a specific lead is properly positioned.
The present invention overcomes the disadvantages of the prior art by providing a method of and apparatus for graphically displaying a visual assessment necessary to determine proper positioning of pacing and/or sensing leads of an implantable medical device system.
The present invention has certain objects. That is, the present invention provides solutions to certain problems existing in the prior art such as: (a) an inability to provide a graphical display of a single cardiac waveform representing a specific portion of the continuous-time waveform corresponding to a single heartbeat, centered on the display; (b) an inability to update the single cardiac waveform based upon a comparison of the heart rate of the patient to specific predetermined rates; (c) an inability to provide a graphical display of the magnitude of the single cardiac waveform; (d) an inability to provide the graphical display of a chosen sensitivity threshold in conjunction with a single cardiac waveform; (e) an inability to provide a graphical display of changes in the sensitivity threshold in conjunction with a single cardiac waveform; (f) an inability to hold the single cardiac waveform, centered on the display; and (g) an inability to print the single cardiac waveform.
The system and method of the present invention provides certain advantages, including: (a) the ability to provide a graphical display of a single cardiac waveform representing a specific portion of the continuous-time waveform corresponding to a single heartbeat centered on the display; (b) the ability to update the cardiac waveform based upon a comparison of the heart rate to specific predetermined rates; (c) the ability to provide a graphical display of the magnitude of the single cardiac waveform; (d) the ability to provide a graphical display of a chosen sensitivity threshold in conjunction with a single cardiac waveform; (e) the ability to provide a graphical display of changes in the sensitivity threshold in conjunction with a single cardiac waveform; (h) the ability to hold the single cardiac waveform centered on the display; and (i) the ability to print the single cardiac waveform.
The system and method of the present invention has certain features, including a graphical display of a single cardiac waveform representing a specific portion of the continuous-time waveform corresponding to a single heartbeat at a time during a pacemaker implant. In addition, the present invention permits selection of the heart passageway from which to view the waveform. Another feature of the present invention is a graphical display of the voltage magnitude of the single cardiac waveform, as well as an expanded version of the single cardiac waveform used to determine the proper position of a lead. Another feature of the present invention is the ability to utilize the heart rate of the patient such that the single cardiac waveform is continuously updated in a manner in which an operator can view the waveform to determine proper location of a pacing or sensing lead. Another feature of the present invention is a graphical representation of a chosen sensing threshold superimposed onto a single cardiac waveform to assist in positioning of a pacing or sensing lead. Another feature of the present invention is the ability to graphically display an updated and modified sensing threshold. Another feature of the present invention is the ability to freeze the single cardiac waveform and superimposed sensing threshold and print a single cardiac waveform and superimposed sensing threshold for further analysis.
Other objects, advantages, and features of the invention will become apparent by referring to the appended drawings, detailed description, and claims.